Electrode



J. S. CAPE.

ELECTRODE.

APPLICATION FILED NOV; 5, 1919.

Patented Sept 13, 19251.

LSQOAZQ.

JOSEPH STANLEY CAPE, OF DETROIT, MICHIGAN.

ELECTRODE.

1,390,429. Specification of Letters P en Patented Sept. 13, 1921.

Application filed November 5, 1919. Serial No. 335,881.

To all whom it may concern:

Be it known that I, JOSEPH STANLEY CAPE, a subject of the King of Great Britain, residing at Detroit, in the county of WVayne, and State of Michigan, have invented certain new and useful Improvements in Electrodes, of which the following is a specification.

This invention relates to electrodes for electro therapeutic apparatus. Heretofore it has been customary in the so-called violet ray machines, which are high frequency machines, to use either a glass vacuum electrode or else a metal electrode. The glass vacuum electrode does very well but cuts down the strength of the current almost onehalf, due to the resistance ofthe rarefied air which acts as a conductor. Hence when it is desired to obtain the full effects of the current it has been customary to use a metal electrode. This metal electrode is satisfactory except where a patient becomes grounded, in which case he is very liable to get a severe shock.

It 'is the object of the present invention to afford an electrode which has practically all the advantages of the metal electrode and at the same time affords complete immunity against undue shocks from grounding of the primary current through the body. This will be explained more in detail after the apparatus has been described.

In the drawings,-

Figure l is an elevation partly in section of the electrode.

Fig. 2 is a diagrammatic view showing the electrode in connection with the apparatus for transforming the current into a high voltage high frequency current.

The electro-therapeutic apparatus that is known as the violet ray machine is a machine provided with a magnet coil and core a, an interrupter arm 5, an armature block 0, an interrupter contact block d, a terminal contact block 6, a condenser f and transformer 9. As indicated by the diagram shown in Fig. 2, the ordinary current for domestic use can be used. The circuit runs around the magnet a and thence to the interrupter terminal contact block e and the binding post it in contact with the armature arm 6. The condenser f is bridged across} the interrupter gap by being connected at one end to the interrupter contact 6 and at the other end to the binding post h. The

.trode.

condenser has the primary winding of the transformer f/ in series.

=In a machine of this character the magnet a operates in the ordinary way to makeand break the circuit at the interrupter gap. The condenser 7' being bridged across this gap, the current from the condenser is caused to surge back and forth across this gap, resulting in a current of very high frequency and high voltage. The transformer 9 serves to step this current up to a still higher voltage, resulting in a high frequency high voltage current, which is very well adapted for therapeutic use. V hen a vacuum glass electrode is used, this high frequency high voltage current induces av static charge on the outside of the glass electrode which will discharge into the body of the patient in the form of highly illuminatedstreaks or sparks that gives to the apparatus the name of violet ray machine.

It has been found in actual practice that with a vacuum glass electrode the current is cut down almost in half due to the resistance of the rarefied air in distributing the current throughout the interior of the elec- Hence when it has been desirable to have the full effect of the current for the patient, it has been customary to use a metal electrode. With such an electrode practically the full effect of the current is secured and the results are satisfactory provided the patient does not become grounded. It will be noticed from the diagrammatic view shown in Fig. 2 that the secondary circuit of the transformed g is grounded in the primary circuit. This is the construction of practically all apparatus of this character. Hence when the patient accidentally touches any object that is grounded a connection is established directly from the primary circuit through the patients body. He will then get a very serious shock due to the passage of alow frequency alternating or direct current from the primary circuit directly to ground through the patients body, shorting the high frequency apparatus. 'It is the purpose of the present invention to afford an electrode which has practically all the advantages ofametal electrode but absolutely protects the patient from the dangers of grounding the current in the primary circuit.

To this end an electrode having a sealed glass tube j is provided. The interior of this glass tube is highly rarefied so that it is substantially a vacuum. Within the tube is an aluminum wire z' secured at one end to the metal cap k for the tube and at the other end forming a coil Z substantially filling the bore of the tube. It is found in actual experiments that this electrode is practically the equivalent of the metal electrode for allowing the full strength of the high frequency high voltage current to be received by the patient for the coil lies close ly contiguous to the inside wall of the glass tube and allows practically no gap between the conductor and the glass. On the other hand, the glass interposes a dielectric which affords a successful barrier to any flow of current from the primary circuit if the patients body should become grounded.

It would not be absolutely necessary to use a vacuum tube, if the conductor abuts the glass all along the interior, but as this cannot be exactly realized except by metal coating the interior, it is much better to use a rarefied tube which very materially cllits down any gap between conductor and g ass.

The essential feature of my invention is a metal conductor in place of a rarefied atmosphere as a conductor, and the conductor arranged for as great a distribution of the high frequency current over the interior of a dielectric body of the electrode as possible.

Vacuum tube is used in the specification and claims in a popular but slightly inaccurate sense of ararefied atmosphere as no so called vacuum tube is an absolute vacuum.

What I claim is:

1. In a high frequency electro-therapeutic apparatus, an electrode comprising a glass vacuum tube and a metallic coil therein lying contiguous to and substantially against the interior face of the glass wall.

4. In an electro-therapeutic apparatus, the combination of a primary circuit of a transformer, a secondary circuit of the transformer grounded in the primary, an electrode connected with the end of the secondary circuit and comprising a vacuum tube of dielectric material and a coiled conductor within the tube distributed over the interior face of the tube in close proximity therewith.

5.. In an electro-therapeutic apparatus, the combination of a primarycircuit of a transformer, a secondary circuit of the transformer grounded in the primary circuit, and an electrode connected with the end of the secondary circuit, comprising a vacuum tube constructed of dielectric material and a conductor coil contained within the vacuum tube and running along the interior face of the tube in substantial contact therewith.

In testimony whereof I aflix my signature.

JOSEPH STANLEY CAPE, 

